21121110111021 has 16 divisors (see below), whose sum is σ = 28182471168000. Its totient is φ = 14070247733808.

The previous prime is 21121110110999. The next prime is 21121110111047. The reversal of 21121110111021 is 12011101112112.

It is a de Polignac number, because none of the positive numbers 2^k-21121110111021 is a prime.

It is a super-2 number, since 2×21121110111021² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21121110111061) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 26486310 + ... + 27272088.

It is an arithmetic number, because the mean of its divisors is an integer number (1761404448000).

Almost surely, 2^{21121110111021} is an apocalyptic number.

It is an amenable number.

21121110111021 is a deficient number, since it is larger than the sum of its proper divisors (7061361056979).

21121110111021 is a wasteful number, since it uses less digits than its factorization.

21121110111021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 792448.

The product of its (nonzero) digits is 8, while the sum is 15.

Adding to 21121110111021 its reverse (12011101112112), we get a palindrome (33132211223133).

The spelling of 21121110111021 in words is "twenty-one trillion, one hundred twenty-one billion, one hundred ten million, one hundred eleven thousand, twenty-one".